Sunless tanning agents are formulated into two types of cosmetic products. Of these, the most traditional is the self-tanning lotion. The imparted benefit is to achieve a skin coloration equivalent to that from basking in the sun. More recently, a second product category has arrived. Therein a sunless tanning agent in small amounts is added to a typical moisturizing lotion. A “glow or shine” is thereby imparted. Glow or shine is a major factor in the appearance of healthy looking skin.
Most prominent among the sunless tanning agents is dihydroxyacetone (“DHA” which is also chemically known as 1,3-dihydroxy-2-propanone). DHA, after application, is believed to exert its effect through interactions between, for example, its keto group and the amino groups of amino acids and peptides naturally occurring in the stratum corneum of the skin. These so-called Maillard reactions are believed (see, e.g., Bobin et al., J. Soc. Cosmet. Chem. 35: 255 (1984)) to lead to formation of brown pigments in the skin, thereby giving it an appearance similar to that of a naturally obtained tan.
Unfortunately, many sunless tanning products available on the market are not stable in that they turn a yellow and/or orange color after application, especially when exposed to UV light. Other sunless tanning products perform poorly and do not quickly impart a noticeable brown color after application. These poorly performing products do not discourage “tan-happy” consumers from basking in the sun. Such behavior then leads to consumers with skin over exposed to the sun's harmful ultraviolet rays.
There is increasing interest to develop compositions and methods for imparting a sunless tan. This invention, therefore, is directed to a composition and method that employ a sunless tanning agent as well as an adjuvant for the sunless tanning agent. The composition, when applied, unexpectedly results in the consumer having skin with a natural brownish/tan coloration within a consumer acceptable time and, surprisingly, does not turn orange and/or yellow after application.
Additional Information
Efforts have been disclosed for making self-tanning cosmetic compositions. In U.S. Pat. Nos. 5,232,688 and 5,612,044, self-tanner compositions with DHA are described.
Other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 5,750,092, compositions with DHA and secondary amines are described.
Still other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 6,231,837, self tanning formulations comprising DHA, polyethoxyglycol and a polyol are described.
Even other efforts have been disclosed for creating sunless tans. In U.S. Pat. Nos. 5,645,822 and 5,756,075, and Published Patent Application No. 2005/0089486, sunless tanning concepts are described.
None of the additional information describes a method and/or composition that yield excellent sunless tanning results whereby the composition and method employ a sunless tanning agent and a vicinal diamine as claimed herein.